feat: centralize isPlaylistUrl function as a helper that could be upgraded in the future

server/helpers/playlist.helpers.js

@@ -0,0 +1,12 @@
+/**
+ * Determines whether a URL targets a playlist.
+ *
+ * The detection is based on the presence of the YouTube
+ * playlist query parameter (`list`).
+ *
+ * @param {string} url - URL to inspect.
+ * @returns {boolean} True if the URL appears to be a playlist.
+ */
+export function isUrlPlaylist(url) {
+    return url.includes("?list=") || url.includes("&list=") || url.includes("@");
+}